Is APRS a Closed World ?

I have been wanted to get into APRS for some time, however most of the information on the net that I can find relates to the USA, Canada, Australia or New Zealand. I have found that if you ask other Radio Amateurs who are also into APRS they offer help, however when I have asked its been rarely given.

Another confusing issue appears to be the requirement for an Nov and Callsign for a IGate or a Digipeater, every time I ask the question I get a different answer.